Currently, bio-diesel is competitively developed worldwide and produced, and even in Korea, the production of bio-diesel has been already begun and bio-diesel is commercially available as an additive of diesel oil.
In the procedure of producing bio-diesel, a great quantity of glycerol corresponding to about 10% of the production amount of the bio-diesel is produced. However, glycerol is excessively supplied in view of the demand thereof, and thus, the value of glycerol continuously decreases. Accordingly, there is a need to increase added-value of glycerol by converting glycerol into chlorohydrins, such as dichloropropanol.
Meanwhile, chlorohydrins, such as dichloropropanol, are used as a raw material for preparing epichlorohydrin, and the most of commercially available chlorohydrins are prepared from propylene. In particular, a method for preparing chlorohydrins includes preparing allyl chloride by high-temperature chlorination reaction of propylene and reacting the allyl chloride with a chlorination agent by using excess industrial water to prepare chlorohydrins. However, the method for preparing chlorohydrins using propylene has many problems including an unstable supply of propylene due to its price increase, generation of great quantities of waste water and waste matter, and excessive initial investment costs due to the two-step method and resulting difficulty in newly constructing/modifying manufacturing apparatuses.
Accordingly, a one-step method for directly preparing chlorohydrins including reacting polyhydroxy aliphatic hydrocarbon, such as glycerol, which is a by-product of bio-diesel, with a chlorination agent in the presence of a catalyst is economical. The one-step method for preparing chlorohydrins by using polyhydroxy aliphatic hydrocarbon, such as glycerol, as reaction raw materials may have lower manufacturing costs due to the use of cheap polyhydroxy aliphatic hydrocarbon. In addition, during the preparation process, industrial water is not used, and thus, generation of waste water and waste matter may be predominantly reduced, thereby being environmentally friendly. Furthermore, the one-step method may contribute to a decrease in process and environment-related investment costs, leading to a lower initial investment costs.
However, the method for preparing chlorohydrins produces water as a by-product and the generated water inhibits a chlorination reaction of polyhydroxy aliphatic hydrocarbon, such as glycerol, so that as the reaction progresses, the reaction rate gradually decreases, the reaction time increases, and selectivity of chlorohydrins decreases.